MR Imaging–Based Evaluations of Olfactory Bulb Atrophy in Patients with Olfactory Dysfunction

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Fig 1.
Atrophy of the olfactory bulbs. Compared with a patient with normal olfactory bulbs (A), which have an oval or inverted-J shape, patients with atrophy in the olfactory bulbs show asymmetric decreases in the size of the affected olfactory bulbs (B, right; and C, left, arrow) or flattening of the olfactory bulbs (D, arrows).
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Fig 2.
Neuropathy of the olfactory bulbs. Homogeneous signal intensity in both olfactory bulbs is noted in a patent without neuropathy (A); however, focal (B) or diffuse (C) hyperintense areas in left olfactory bulb (arrow) compared with the white matter of the frontal lobe are visible on FLAIR images in patients with neuropathy.

Table 2:

Comparison of subjective symptom severity between patients with normosmia and those with hyposmia/anosmia^{^a}

Note:—SNOT-22 indicates Sino-Nasal Outcome Test-22.
↵a LQ = LQ raw score/0.57 (%); Sincerity = Sincerity raw score/0.18 (%); Parosmia score = Parosmia raw score/0.12 (%).
↵b Mann-Whitney U test.

Table 3:

Comparison of Korean Version of the Sniffin' Sticks II test scores according to the presence/absence of olfactory bulb atrophy

	Normal	Atrophy	P Value^{^a}
Threshold	8.1 ± 5.9	3.8 ± 5.1	.030
Discrimination	9.6 ± 2.8	6.7 ± 2.9	.006
Identification	9.1 ± 3.9	5.7 ± 2.5	.006
Total Threshold-Discrimination-Identification score	26.9 ± 11.9	16.2 ± 8.8	.008

Table 4:

Atrophy and neuropathy of the olfactory bulb on MR images according to the Korean Version of the Sniffin' Sticks II test results and etiology^{^a}

Etiology	Normosmia	Hyposmia/Anosmia	P Value^{^b}
Chronic rhinosinusitis (n = 15)
Atrophy	0/4 (0)	7/11 (63.6)	.077
Neuropathy	1/4 (25.5)	3/11 (27.3)	1.000
Postviral URI (n = 7)
Atrophy	1/3 (33.3)	3/4 (75.0)	.486
Neuropathy	2/3 (66.7)	1/4 (25.0)	.486
Trauma (n = 2)
Atrophy	0/0 (0)	1/2 (50.0)	NA
Neuropathy	0/0 (0)	0/2 (0)	NA
Idiopathic (n = 10)
Atrophy	0/3 (0)	6/7 (85.7)	.033
Neuropathy	1/3 (33.3)	1/7 (14.3)	1.000